pub enum ConstValue<'tcx> {
    Scalar(Scalar<AllocId>),
    ZeroSized,
    Slice {
        data: ConstAllocation<'tcx>,
        start: usize,
        end: usize,
    },
    ByRef {
        alloc: ConstAllocation<'tcx>,
        offset: Size,
    },
}
Expand description

Represents a constant value in Rust. Scalar and Slice are optimizations for array length computations, enum discriminants and the pattern matching logic.

Variants§

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Scalar(Scalar<AllocId>)

Used only for types with layout::abi::Scalar ABI.

Not using the enum Value to encode that this must not be Uninit.

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ZeroSized

Only used for ZSTs.

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Slice

Fields

§data: ConstAllocation<'tcx>
§start: usize
§end: usize

Used only for &[u8] and &str

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ByRef

Fields

§alloc: ConstAllocation<'tcx>

The backing memory of the value, may contain more memory than needed for just the value in order to share ConstAllocations between values

§offset: Size

Offset into alloc

A value not represented/representable by Scalar or Slice

Auto Trait Implementations§

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impl<'tcx> RefUnwindSafe for ConstValue<'tcx>

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impl<'tcx> Send for ConstValue<'tcx>

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impl<'tcx> Sync for ConstValue<'tcx>

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impl<'tcx> Unpin for ConstValue<'tcx>

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impl<'tcx> UnwindSafe for ConstValue<'tcx>

Blanket Implementations§

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impl<T> Any for Twhere T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for Twhere T: ?Sized,

const: unstable · source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for Twhere T: ?Sized,

const: unstable · source§

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

const: unstable · source§

fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for Twhere U: From<T>,

const: unstable · source§

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> ToOwned for Twhere T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for Twhere U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
const: unstable · source§

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
const: unstable · source§

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.

Layout§

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference’s “Type Layout” chapter for details on type layout guarantees.

Size: 32 bytes

Size for each variant:

  • Scalar: 24 bytes
  • ZeroSized: 0 bytes
  • Slice: 24 bytes
  • ByRef: 16 bytes